#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    string a, b;
    cin >> a >> b;
    cout << ((a[0]-b[0])%2 == 0 ? "Possible" : "Impossible") << endl;

    return 0;
}